Early Cenozoic Tectonics and Paleogeography of the Pannonian and Surrounding Regions
Published:January 01, 1988
L. H. Royden, T. Báldi, 1988. "Early Cenozoic Tectonics and Paleogeography of the Pannonian and Surrounding Regions", The Pannonian Basin: A Study in Basin Evolution, Leigh H. Royden, Ferenc Horváth
Download citation file:
A series of palinspastic and paleogeographic reconstructions has been made for the Pannonian and surrounding regions for five time periods: (1) Coniacian-Paleocene, (2) early-middle Eocene, (3) late Eocene-early Oligocene, (4) late Oligocene-early Miocene, and (5) late Miocene. These maps were constructed by grouping together various crustal blocks that underwent similar phases of deformation or sedimentation into tectonostrati-graphic units. We show how the present complex distribution of Mesozoic tectonostratigraphic units could have developed from a simple initial configuration during Cenozoic deformation of the Carpathian-Pannonian region, and that the formation, duration, and disruption of various Paleogene paleogeographic elements can be directly related to contemporaneous tectonic events.
In this analysis we interpret the elongate Hungar, ian Paleogene basin as a wrench related basin that formed along an east, northeast, trending zone of dextral shear in Eocene-Oligocene time. This shear zone was probably responsible for the Paleo-gene dislocation of the Apuseni Mountains from the inner West Carpathians. We further interpret the Pieniny Klippen belt as the result of conver, gence and sinistral shear active in part during Eocene time. This analysis suggests that the inner flysch zones (podhale flysch, Szolnok, Maramures flysch, and Transcarpathian flysch) originally con, stituted a continuous flysch basin that was subse, quently disrupted by roughly east, northeast, trending dextral shear zones.
Large shear zones such as those postulated in this paper are required partly because of the diachro, nous nature of the convergent boundary extending from the Eastern Alps to the East Carpathians and partly because of the different directions of thrusting around the belt. These shear zones separate areas of active shortening in the outer Carpathian orogenic belt from inactive parts of the belt and also act as transform type boundaries that connect areas of shortening in the Carpathians to areas of short, ening in the Dinaric Alps. The existence of such shear zones can thus be deduced almost directly from analysis of the varying rates and directions of convergence across the Carpathian belt.
Figures & Tables
The Pannonian Basin: A Study in Basin Evolution
The Pannonian basin system is an integrap part of the Alpine mountain belts of east-central Europe. It is completely encircled by the Carpathian Mountains to the north and east, the Dinaric Alps to the south, and the Southern and Eastern Alps to the west. In 1912, Kober defined the Pannonian basin as one of the type “Zwischengebirge,” a relatively un-deformed region characterized by block faulting and situated between externally vergent thrust belts. More recent studies using subsurface data have shown that the Pannonian area was extensively deformed by Mesozoic thrusting and subsequently disrupted by a complex system of Cenozoic normal and wrench faults. Thus, the Pannonian “massif” has undergone several types of deformation, which are partly hidden by a thick sequence of sedimentary rocks of Neogene-Quaternary age. The Pannonian basin is actually a system of small, deep basins separated by relatively shallow basement blocks. The Neogene-Quaternary sedimentary rocks exceed 7 km in thickness in some areas, and the basin system (including the Transylvanian basin) is about 400 km from north to south and 800 km from east to west. It is currently interpreted by most workers as a Mediterranean back arc extensional basin of the middle Miocene age. The Carpathians, Eastern Alps, and Dinarides, which surround the Pannonian basin, are the result of Mesozoic and Cenozoic continental collision between Europe and several continental fragments to the south, including Africa. Thrusting was direted outward from the present Pannonian basin toward the European platform and the Adriatic region. In all the orogenic belts, the interior parts of the thrust belts were deformed in Mesozoic time, while the outer parts were deformed in Tertiary time. The volume presents 26 papers and eight regional maps resulting from a joint five-day symposium held in Veszprem, Hungary, in 1982 entitled “Evolution of Extensional Basins within Regions of Compression with Emphasis on the Intra-Carpathian Region.” The symposium was sponsored jointly by the Hungarian Oil and Gas Trust, the Hungarian Geological Survey, and the U.S. National Science Foundation.